Moisture and particle removing means for engines



p 1 D. A. RICHARDSON EI'AL 3,143,043

MOISTURE AND PARTICLE REMOVING MEANS FOR ENGINES Filed March 29, 1962DAVID A RICHARDSON WILLIAM G. WILKJNS INVENTORS ATTORNEY WCM UnitedStates Patent 3,148,043 MOISTURE AND PARTICLE REMOVING MEANS FGR ENGDavid A. Richardson, Wayne, and William G. Wilkins,

Clifton Heights, Pa, assignors to The Boeing Company, Seattle, Wash, acorporation of Delaware Filed Mar. 29, 1962, Ser. No. 183,641 Claims.(Cl. 55-306) This invention relates to separating means for an airstream and, moreparticularly, is directed to new and novel means forremoving deleterious bodies and sub stances from the intake air streamof gaseous power plants such as jet or turbine engines though notlimited to such applications.

The ingestion of foreign particles and moisture into gas turbine or jetengines is a most serious problem since foreign particles, such as dirt,sand, water, and the like, materially shorten the life of variouselements of the engine, for example, the blades of the compressor. Suchforeign particles or moisture can cause multitudinous damage, such aspitting, corrosion, fouling of various engine pants, and other seriousproblems.

The problem of ingested foreign particles and moisture is universal toall types of jet or gas turbine engine usages; however, the problem isparticularly troublesome in helicopter applications. The unique hoveringcharacteristics and ability to land and take-off from most any type ofterrain or body of water makes the jet or gas turbine powered helicopterparticularly susceptible to the aforementioned problems created byparticles and moisture.

Thus, if a helicopter were to hover, land, or take-off from a body ofsalt water, the ingestion of salt water is the result with salt beingdeposited on the compressor blades causing performance losses.Similarly, if the helicopter is operated from land bases, such asbeaches, fields, mountainous terrain, or the like, the engine intakewill be contaminated by an ingestion of dirt, small particles of stone,sand, or similar material with the consequent result of serious pitting,fouling, or in some instances the initiation of fractures to delicateprecision elements of the engine.

Evident of the recognition of some of the aforementioned problems andtypical prior art efforts to solve them are United States Letters PatentNo. 2,944,731 issued to Howard Kastan and United States Letters PatentNo. 2,997,229 issued to- Dick Quan. The patent to Quan is directed toand discloses means for separating moisture from a surface traversed bya gaseous flow, thereby indicating that Quan recognized the detrimentaleffects of moisture on a turbine engine. The patent to Kastan pro videsa novel trap or sump that is an external appendage to the turbine or jetengine having an opening into the intake air stream duct of the engine.The Kastan device is primarily directed to the collection of relativelylarge or heavy materials such as sticks, loose bolts, hail stones, andlike debris. The very weight of this debris will cause it to be draggedalong the lower end of the intake air duct from which it will fall, bygravity, into the debris collecting sump.

The present novel invention also recognizes the prob lems aforesaid andoffers a unique and novel means for effectively and concomitantlypreventing the admission of both moisture and small extremelydeleterious foreign particles into the engine system. Further, the novelstructure herein disclosed offers unique means for simultane- 'icedelicate moving parts of the engine. Further, this novel structure isconstructed and located in recognition of the existence or lack thereofof a coefficient of restitution in the bodies to be removed. Thus, aswill hereinafter become readily apparent, there is herein disclosed aunique and novel invention that will effectively remove moisture andforeign particles from the intake air of a power plant such as jet orturbine engines, that is simple in construction, inexpensive tomanufacture, highly eflicient in its operation, and that minimallylessens the efficiency or power of the engine.

It is a primary object of the present invention to provide novel meansfor removing moisture and foreign particles from the air intake of apower plant such as a jet or turbine engine well before the air streamreaches the delicate moving parts of the engine.

Another object of the present invention is to provide new and novelstructure for separating foreign particles and moisture from the airintake of a power plant such as a turbine engine in which the novelstructure takes advantage of the presence or lack of presence of acoefficient of restitution in the substances to be removed.

An additional object of the present invention is to provide novelstructure that functions with and makes use of the cowl and-conestructure of a jet or turbine engine intake, well forward of the engineelements, for separating moisture and foreign particles from the intakeair stream with minimal loss of efficiency or power of the engine.

Yet a further object of the present invention is to provide the intakeof a gaseous power plant such as a jet or turbine engine with a pair ofnovel collector elements, within the intake duct space well forward ofthe engine elements, which efficiently removes moisture and foreignparticles from the intake air stream.

Still an additional object of the present novel invention is to provide-a novel moisture collecting annulus incorporated in the intake cone ofa jet or turbine engine, and a novel annular debris collector ringmounted in a predetermined relationship with the engine cowl and cone,well forward of the moving elements of the engine.

Still another object of the present invention is to pro vide an annularlip on the cone in the intake of a jet or turbine engine to collectmoisture from the intake air, and an annular collector ring aft of thecone and in a predetermined relationship with the engine cowl and cone,whereby air borne particles are rebounded from the cone and innersurface of the cowl and into the annular collector ring, therebyremoving deleterious particles from said air before the intake airreaches the operational portion of the engine.

These and other objects of the present novel invention will readilyappear from a reading of the following detailed description when read inconjunction with the attached drawing wherein:

FIGURE 1 is a fragmentary plan view of a gas turbine type engine,partially broken away to show the novel collector element; FIGURE 2 is aschematic view of the intake of a turbine engine showing therelationships of the various elements of the novel separator means ofthis invention, and graphi cally showing the path of moisture anddeleterious particles into the moisture separator and particlecollector, respectively;

FIGURE 3 is a fragmentary cross sectional view of a portion of the novelparticle collector ring of the present novel invention showing thedetails of construction thereof;

FIGURE 4 is a fragmentary perspective view of the intake end of aturbine engine with the cowl element partially broken away to furthershow the relationship of the various elements of the novel collector andseparator of the present invention; and

FIGURE 5 is a fragmentary sectional view taken essentially along theline 55 of FIGURE 1 showing the carry olf duct for carrying off thedeleterious particles collected in the collector ring.

Referring to the drawing, wherein like numerals indicate like parts, thenumeral generally indicates a gas turbine engine. Since this inventionis directed to novel means for separating moisture and debris from theintake air before it reaches the operational portion of the turbine,only those portions of the turbine engine pertinent to this inventionare illustrated in detail and will be described.

As clearly seen in the drawing, the turbine It is provided with acowling portion 14, which defines an intake opening, through which theintake air for turbine It) is drawn. Mounted within the cowl 14 is acone member 20, which is well known in the turbine or jet engineconstruction. The cone 2i and inner surface 22 of the cowl 14 define anannular passage 24 through which the intake air passes. It will be notedthat the cone 29 increases in diameter from its point or apex 26 to amaximum diameter 28 within the cowl 14, and further that the innersurface 22 of the cowl 14 also similarly increases in diameter as itextends inboard. Thus, the annular air intake space is of everincreasing diameter as the passage progresses inboard.

Beyond diameter 28 of the cone the cone assumes a reverse conicalconstruction and decreases in diameter in a smooth curve as indicated bythe numeral 34. The inner surface 22 of the cowl 14 is verticallyinwardly disposed at its inner end, as indicated by the numeral 3-6, andthen horizontally bent to define a collar or sleeve portion 38. Thecollar or sleeve portion 33 together with the surface 34 of the cone 2iserve to define a second annular passage 40, which is of, or located at,a lesser diameter with respect to the annular passage 24.

Mounted on the outboard or leftmost face of part 36, as viewed in FIGURE1, is an annular receptacle 42 for collecting or receiving separateddirt, debris, or the like, the function of which will readily becomeapparent hereinafter. As also clearly seen in FIGURE 1, the annularcollector ring 42 is mounted on the part 36 on the same diameter as thecollar or sleeve portion 38 and with the sleeve portion 38 helps todefine the annular passage 40.

Referring to FIGURE 3, there is shown, in cross section, an enlargedportion of the collector ring 42, the details of which will now bedescribed with reference to parts shown in other figures. An annularfiange 44 is fixedly secured to the part 36 as by welding or othersuitable means. Extending outboard (to the left, as viewed in FIGURE 3)from the flange 44 is a horizontally disposed portion 46 of essentiallythe same diameter as the sleeve portion 38. At the end of the collarportion 46, the collector ring 42 is angularly disposed or bentdiametrically outwardly as at 48, extending toward the inner surface 22of the cowl 14, and the very end thereof is reversely bent inboardhorizontally as at 50 terminat ng in a lip portion 52. The configurationof the collector ring 42 essentially defines an annular chamber or trap54 for debris and the overlying portion 50 and the lip 52 effectivelyprevent particles collected therein from escaping into the intake air aswill hereinafter readily appear.

Referring to FIGURES 1, 2, and 4, the details of the moisture collectingstructure of the cone 20 will now be particularly described. As clearlyseen in FIGURE 2, the cone 20 is provided with an annular opening 56inboard of its tip 26 and approximately adjacent its maximum diameter28. Moisture in the intake air, having no coefficient of restitution,will strike the cone and essentially adhere thereto and move inboardalong the cone surface and pass through the opening 56, which has a lipF, as will hereinafter be described and will readily appear.

As is seen, the lip F on cone 2i) is at a greater diameter than the conesurface 58 to the left thereof so that the opening 56 is essentiallydirectly in the path of the cone surface 58, extended. It has been foundthat the width of the opening 56 will give optimum efiiciency when aboutone-tenth of an inch (.10).

With continued reference to FIGURE 2, the maximum diameter C of the cone29 is designed to be not less than 75% of the initial or openingdiameter A of the turbine intake. The relationship of diameter C todiameter A helps to properly control the directional flow of the intakeair from its original inward path toward the cone to a reverse oroutward path toward the inner surface 22 of the cowl 14.

Further, the acute angle B, which designates the angle of inclination ofthe surface 53 of the cone 20, also determines the location of thecollector ring 42. It has been found for optimum efi'iciency that thecollector ring 42 must lie within the acute angle B; in other words, aline of the surface 58 extended, as indicated by broken line 6%, willpass between the collector ring 42 and the inner surface 22 of the cowl14.

Additionally, the width of the annular passage 24, between surfaces 58and 22 designated by the letter G. shall not be greater than thestraight line distance connecting points H and F, H being the point ofthe initial opening diameter of the engine intake. It also has beendetermined for the maximum effectiveness in collecting the moisture inthe intake air that the lip F should be located forward of theintersection of the acute angle B, extended (broken line 6%), with thecurved surface 34 as designated by the numeral 62 in schematic drawingFIGURE 2.

In operation, intake air is drawn into the turbine at a relatively highspeed. It also has been found that the major volume of the intake airdrawn into the turbine actually comes from the area away from the centerline of the intake and not on a direct line; the intake air stream beingdesignated by the numeral 70 in FIGURE 2. The effect of this high speedflow of air flowing essentially toward the cone 26 is to impart acentrifuging action to the air and consequently a centrifuging action toany airborne particles. The eifective path of particles in the intakeair is designated by the heavy dash-dot lines 72 in FIGURE 2.

As clearly shown in FIGURE 2, the air-borne particles strike the surface58 of the cone 20; the particles then rebound from the surface 58 towardthe inner surface 22 of the cowl 14; and next rebound from the innersurface 22 of the cowl 14 toward the receptacle 54 of the collector ring42. This action of the particles is due to the fact that small air-borneparticles have an inherent coelficient of restitution and upon strikinga surface with a relatively high velocity will rebound from the surface.Of course, depending upon the angle of incidence, the angle ofreflection from the surface58 of the cone 20 will vary; thus some of theparticles will rebound directly from the surface 58 into the trap 54while others will rebound from the surface 58 to the inner surface 22and therefrom into the receptacle 54.

Once the particles have passed into the receptacle 54 of the collectorring 42, they will accumulate by gravity at the lower end of thecollector ring. As disclosed in FIGURE 5, the lower end of the turbineengine is provided with a duct 66, which opens towards the mouth ofreceptacle 54, and the collected particles 68 pass from the receptacle42 into the duct 66, and from the duct to a suitable collectingcontainer (not shown), which can be conveniently removed from theturbine engine when filled.

With this novel means of separating deleterious particles from theintake air, it has been found that ninety percent of the more harmfulparticles in the intake air having a size of 25 microns or greater areremoved with a total intake loss of efficiency not exceeding six-tenthspercent (0.6%). Thus, the air traveling into the operational portion ofthe engine designated by the numeral 76 is ninety percent purified ofharmful patricles of the order of 25 microns or greater.

Moisture in the intake air, designated in FIGURE 4 by the numeral 74,also has a centrifuging action imparted thereto by the effect of thehigh speed in flow of intake air as heretofore described. However,moisture or droplets do not possess an inherent coefficient ofrestitution so that the net result is that when the moisture particlesor droplets strike the surface 58 of the cone the moisture adheresthereto and travels along the surface 58, inboard, with the generalinflow of intake air. Thus, moisture striking the surface 58' willtravel along the inclined surface 58 of the cone 20; eventually, inwardflow will be effectively prevented by the lip F and the opening 56. Themoisture and droplets will flow through the opening 56 as indicated bythe dash lines designated 74 in FIGURES 2 and 4. Thus, the moisture willpass from the exterior surface 58 of the cone 29 into the interior ofthe cone N where it can be collected by gravity and ducted or drawn offto a suitable container (not shown) essentially similar to that shown inFIGURE 5 for the debris and particles. It has been found,experimentally, with the moisture separator as aforedescribed that 90%to 100% of the droplets on the order of microns in size and greater areeffectively removed from the intake air.

Thus, it is readily seen from the foregoing description that there isprovided a new, unique, and novel invention for the separation ofmoisture and debris from the intake .air of jet or turbine engines. Italso is readily appreciated that this novel invention embodies uniquesimple structure that makes maximum use of the confined space within theintake opening of jet or turbine engines to provide inexpensiveseparating means so that no expensive, large, and efiiciency reducingappendages need be attached ,to the external portions of the engine orhelicopter.

While the invention has been desribed with respect to members ofcircular type shape, it should be understood that the members could haveother configurations. For example, the cowl 14 and the cone 2t) couldhave a rectangular shape. Thus, the term annular in the claims andspecification should be understood to mean any passage, which is formedbetween two spaced members with one surrounding the other, unlessspecifically directed to members of circular shape. I

This invention may be embodied in other forms without departing from thespirit or essential characteristics thereof. The present embodiments aretherefore to be considered in all respects as illustrative and notrestrictive the scope of the invention being indicated by the appendedclaims, rather than by the foregoing description, and all changes whichcome within the meaning and range of equivalency of the claims aretherefore intended to be embraced therein.

We claim:

1. In combination, an engine having a first air intake passage definedby spaced inner and outer members mounted on a common axis; a secondpassage of lesser size than said first intake passage extending inwardlyfrom an innermost end of said first intake passage and connectedthereto; said two passages defining a continuous path for engine intakeair; barrier means on the periphery of the inner member defining amoisture opening from the exterior thereof to the interior thereof; andcollector means mounted within said first intake passage at the junctureof said two passages; said collector means mounted in inwardly spacedrelation from said outer member and substantially on the outer wall ofsaid second passage; said inner member diverting the flow of intake airoutwardly toward said outer member whereby particles in said intake airrebound from said inner and outer members into said collector meansbefore said intake air reaches the second passage while moisture in theintake air strikes the surface of the inner member and traverses saidsurface and passes through said moisture opening from the exterior tothe interior of said inner member.

2. In combination, an engine having a cowl and an intake cone defining apair of concentric annular air intake passages; a first of said passagesextending inwardly from an open end of said engine a predetermineddistance in increasing diameter; the second of said annular passagesconnected to the innermost end of said first annular passage andextending therefrom into said engine at a lesser diameter than saidfirst annular passage; barrier means on the circumference of said conedefining a moisture opening from the exterior thereof to the interiorthereof; an annular collector member mounted at the innermost end ofsaid first annular passage substantially at the juncture of said twoannular passages and in spaced relation to said cowl whereby intake airdrawn into said first annular passage toward said cone is divertedoutwardly therefrom and thence to said second annular passage andparticles in said intake air rebound successively from said cone andcowl and into said collector member While moisture in said intake airstrikes the surface of said cone and traverses said surface and passesthrough said moisture opening from the exterior to the interior of saidcone.

3. In combination, an engine having a first air intake passage definedby spaced inner and outer members mounted on a common axis; a secondpassage of lesser size than said first intake passage connected theretoand extending inwardly from an innermost end of said first passage; saidpassages defining a continuous path for in take air to said engine; saidinner member having angulated sides increasing in inclination withinsaid outer member; collector means mounted within said first passage atthe juncture of said two passages and lying wholly within an extensionof the angle of inclination of said inner member with respect to thecenter line of the engine; said collector means also mounted in spacedrelation to said outer member whereby inflowing intake air carryingdeleterious particles traversing from said first passage toward saidsecond passage will strike said inner and outer members and theparticles therein will successively rebound therefrom and into saidcollector means.

4. In combination, an engine having a first annular air intake passagedefined by concentrically mounted inner and outer members; a secondannular passage of lesser diameter than said first annular intakepassage'connected thereto and extending inwardly from an innermost endof said first annular passage; said annular passages defining acontinuous path for intake air to said engine; said inner member havingangulated sides increasing in inclination within said outer member;collector means mounted within said first annular passage at thejuncture of said two annular passages and lying wholly within anextension of the angle of inclination of said inner member with respectto the center line of the engine; said collector means also mounted inspaced relation to said outer member whereby inflowing intake aircarrying deleterious particles traversing from said first annularpassage toward said second annular passage will strike said inner andouter members and the particles therein will successively reboundtherefrom and into said collector means.

5. In combination, an engine having a circular cowl member; an intakecone, having a predetermined angle of inclination, mounted Within andextending inwardly in said cowl; said cowl and cone defining a pair ofconcentric annular air intake passages; a first of said passagesextending inwardly from an open end of said cowl a predetermineddistance in increasing diameter; the second of said annular passages, oflesser diameter than said first passage, connected to the innermost endof said first passage and defining therewith a path for the engineintake air; a circumferential lip on and substantially adjacent themaximum diameter of said intake cone defining a moisture opening in saidcone connecting the exterior surface with the interior thereof; said lipextending outwardly at a greater diameter than the surface of said cone;an annular collector ring mounted at the juncture of said two annularpassages and in spaced relation to said cowl; said collector ring lyingwithin an extension of the angle of inclination of said cone and havingan open side facing said cowl; intake air drawn into said engine at highspeed successively moves toward said cone and is then diverted towardsaid cowl before traversing said second annular passage wherebyparticles in said air rebound from said cone and cowl and into the openside of said collector ring and moisture in the intake air traverses thesurface of said cone and passes through the moisture opening from theexterior surface to the interior of said cone.

6. In combination, an engine having an air intake cowl defining asubstantially circular opening; an air intake cone, having apredetermined angle of inclination, mounted in said opening andextending inwardly into said cowl; said cowl and cone defining a pair ofessentially concentric annular air intake passages for said engine; themaximum diameter of said cone being at least seventyfive percent (75%)of the diameter of said circular opening; a first of said annularpassages extending inwardly from an open end of said cone in everincreasing diameter; the second of said annular passages, of lesserdiameter than the first annular passage, connected to the first annularpassage at an innermost end thereof and defining therewith a path forair intake for said engine; a circumferential lip on and substantiallyadjacent the maximum diameter of said cone, said lip extendingdiametrically outwardly beyond the normal angle of inclination of saidcone; a moisture opening beneath said lip connecting the exteriorsurface with the interior of said cone; an annular collector ringmounted within said first annular passage in spaced relation to saidcowl substantially at the juncture of said two annular passages; saidcollector ring having an open side facing said cowl member wherebyparticles rebounding from said cowl surface at different angles willpass through the open side into said collector ring; said collector ringlying wholly within an, extension of the angle of inclination of saidcone whereby intake air drawn into said first annular passage atrelatively high speed moves successively toward said cone and said cowlbefore traversing said second annular passage and particles in theintake air rebound successively from said cone and said cowl and intosaid collector ring while moisture in the intake air, lacking acoefiicient of restitution, traverses the surface of said cone andpasses through said moisture opening from the exterior to the interiorof said cone.

7. The device as set forth in claim 6 wherein the width of the firstannular space between the surface of the cone and an adjacent surface ofsaid cowl is less than the distance from a point on said cowl,representing the outerameter thereof extending diametrically outwardlyand ly-,

ing at an angle of greater inclination than the angle of inclination ofsaid cone; said maximum diameter being at least seventy-five percent ofthe diameter of the open end of said cowl; a circumferential lip on saidenlarged portion substantially adjacent the maximum diameter thereof andfacing said open end of the cowl; said lip and the cone surface, lyingon the angle of inclination of said cone, defining a circumferentialmoisture opening facing the open end of said cowl; said moisture openingconnecting the exterior surface of said cone with the interior thereof;an annular collector ring mounted at the juncture of said two annularpassages and in spaced relation to said cowl; said collector ring lyingwithin an extension of the angle of inclination of said cone and havingan open side facing said cowl; intake air drawn into said engine at highspeed successively moves toward said cone and is then diverted towardsaid cowl before traversing said second annular passage wherebyparticles in said air rebound from said cone and said cowl and into thecollector ring through said open side, and moisture in the intake air,lacking a coefficient of restitution, traverses the surface of said coneand passes from the exterior surface to the interior thereof throughsaid moisture opening.

9. The device as set forth in claim 8 wherein the width of the firstannular space between the surface of inclination of the cone and anadjacent surface of said cowl is less than the distance from a point onsaid cowl representing the outermost diameter of the cowl at the openend thereof and an edge of said lip.

10. The device as set forth in claim 8 wherein said lip faces the openend of said cowl and lies forward of a point determined by theintersection of an extension of the angle inclination of said cone withsaid enlarged portion.

References Cited in the file of this patent UNITED STATES PATENTS2,158,863 Randall May 16, 1939 2,600,302 Kinsella June 10, 19522,616,519 Crankshaw Nov. 4, 1952 2,636,666 Lombard Apr. 28, 1953

1. IN COMBINATION, AN ENGINE HAVING A FIRST AIR INTAKE PASSAGE DEFINEDBY SPACED INNER AND OUTER MEMBERS MOUNTED ON A COMMON AXIS; A SECONDPASSAGE OF LESSER SIZE THAN SAID FIRST INTAKE PASSAGE EXTENDING INWARDLYFROM AN INNERMOST END OF SAID FIRST INTAKE PASSAGE AND CONNECTEDTHERETO; SAID TWO PASSAGES DEFINING A CONTINUOUS PATH FOR ENGINE INTAKEAIR; BARRIER MEANS ON THE PERIPHERY OF THE INNER MEMBER DEFNING AMOISTURE OPENING FROM THE EXTERIOR THEREOF TO THE INTERIOR THEREOF; ANDCOLLECTOR MEANS MOUNTED WITHIN SAID FIRST INTAKE PASSAGE AT THE JUNCTUREOF SAID TWO PASSAGES; SAID COLLECTOR MEANS MOUNTED IN INWRDLY SPACEDRELATION FROM SAID OUTER MEMBER AND SUBSTANTIALLY ON THE OUTER WALL OFSAID SECOND PASSAGE; SAID INNER MEMBER DIVERTING THE FLOW OF INTAKE AIROUTWARDLY TOWARD SAID OUTER MEMBER WHEREBY PARTICLES IN SAID INTAKE AIRREBOUND FROM SAID INNER AND OUTER MEMBERS INTO SAID COLLECTOR MEANSBEFORE SAID INTAKE AIR REACHES THE SECOND PASSAGE WHILE MOISTURE IN ANDTRAVERSES SAID SURFACE AND PASSES THROUGH SAID MOISTURE OPENING FROM THEEXTERIOR TO THE INTERIOR OF SAID INNER MEMBER.